December Gardening Tips for the Pacific Northwest

Gardening slows outdoors in Northwestern gardens in December. But there's still garden fun to be had indoors and out.

Long-lasting Christmas Trees

Not sure how to keep your natural tree soft and green? Start by choosing a fresh tree.

Christmas tree farms

  • Check its needles. On a moist tree, the needles will bend in your fingers; on a dry tree, the needles will snap. Dried out trees lose their needles easily. If you gently grasp a branch and pull on a dry tree, you'll end up with a handful of needles.
  • Cut 1-2 inches off the trunk base when you get the tree home. Store it outside in water until you're ready to decorate. Check the tree stand twice daily to ensure water levels remain constant.
  • Needles will dry out more slowly if you spray them with an antidesiccant product. This applies to fresh garlands and wreaths, too. Also, the warmer the room is where your tree is stored, the faster it will dry out. Try to keep your tree away from fireplaces, heating vents, and other sources of warm air.
  • After the holidays, clip branches from the tree and lay them over planting beds for winter mulch. The boughs provide ideal protection for garden plantings.


Test Garden Tip: If you remove lower branches from your tree, use them to decorate other areas of your home, inside or out. Indoors, protect wood finishes by placing boughs on a piece of fabric or parchment.

Beat the Cold

Outwit winter chill by preparing for cold snaps. A few simple steps can mean the difference between a plant that dies or survives.

Cover plants

  • If a frost warning is issued, water plants before temperatures drop. Plants that are well-watered survive frost better. When frost comes without warning, watering afterwards helps plants survive. Irrigate after plants start to thaw.
  • When you're covering plants for the night, ensure your protective coverings touch the ground. Frost protection covers work by trapping radiant heat in soil. As soil releases its heat, the cover holds the heat around the plant. Use fabric covers, such as plant insulating blankets, burlap, or bed sheets.
  • It's easy and quick to build a shelter around tender plants: Anchor stakes in soil and attach a cover to stakes.
  • Not all plants can withstand the same low temperatures. If temperatures are predicted to drop below 25 degrees F, protect pittosporum, fragrant daphne, and waxleaf privet. If temperatures are predicted to drop below 15 degrees F, protect broadleaf evergreens such as rhododendron, camellia, holly, etc.

Test Garden Tip: When a lawn is frozen or grass blades are frost-covered, keep off. Walking on lawns in this condition can actually damage turf crowns.

Plant for Winter Color

Swiss chard, flowering kale, and 'Marmalade' coralbells

Dress up winter pots, empty vegetable gardens, and flowerbeds with cheerful flowering annuals. Pansies, snapdragon, dianthus, calendula, and viola will stage a pretty show all winter. You can also rely on flowering cabbage and kale to brighten winter scenes.

Tuck a dose of slow-release fertilizer beneath root balls as you plant these colorful beauties to ensure they're well-fed throughout the season.

Add a touch of green indoors by filling a sunny windowsill with potted herbs. Choose varieties you cook with to make the best use of them.

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